Depleted uranium should, perhaps, be the ammunition of choice for duck hunters. That's the conclusion of a study called Response of American Black Ducks to Dietary Uranium: A Proposed Substitute for Lead Shot.

The recommendation, published in 1983 in the Journal of Wildlife Management, has not been much disputed. The study's authors, biologists Susan Haseltine and Louis Sileo, were based at the Patuxent Wildlife Research Centre in Laurel, Maryland.

Lead shot is dangerous for ducks, especially if it hits them. When it doesn't hit a duck (or another hunter, as sometimes happens), the shot falls into the wetlands. The lead leaches into the muck, slowly poisoning any ducks that have managed to avoid being shot.

In many hunting areas, lead shot is verboten. At the time of the study, steel was being touted as the best alternative to lead. But Haseltine and Sileo pointed out its drawbacks. "Steel shot shells are more expensive than lead shot shells when purchased in a retail outlet," they wrote. "They cannot be used in all guns and have not been well received by some hunters, who question their performance on ducks and geese."

Haseltine and Sileo credit the idea of substituting uranium for steel to the metallurgist Dr Carl A Zapffe of Baltimore, Maryland. Zapffe was no slouch about steel: witness his 1948 study Evaluation of Pickling Inhibitors from the Standpoint of Hydrogen Embrittlement: Acid Pickling of Stainless Steel. Zapffe also wrote a book disputing Einstein's theory of special relativity, but that is a separate matter.

Haseltine and Sileo listed what they call the "attractive characteristics" of depleted uranium as a raw material for making birdshot.

"In its pure form," they wrote, "it is denser than lead and, in alloys, might be made to produce shot patterns and velocities attractive to hunters and within the effective range for waterfowl. Depleted uranium can be alloyed with many other metals and its softness and corrosiveness can be altered over a wide range."

But nothing is perfect. "Negative aspects for potential uranium shot include pyrophoricity [proneness to spontaneously burst into flames] problems with pure depleted uranium, which can be altered by alloying, and the expense of separating depleted uranium from other nuclear waste products."

Their main argument was that uranium may not be very poisonous even to a duck that, of its own accord, swallows some in pellet form. That is what Haseltine and Sileo sought to verify.

They fed 40 ducks a diet of commercial duck mash salted with powdered depleted uranium. None of the ducks died of it, or got sick, or even lost weight. Moreover, the researchers reported, the ducks "were in fair to excellent flesh" when slaughtered.

And so they enthused that "further examination of this metal as a substitute for lead in shot is justified".

However, no one has yet followed up on this in a big way for hunting anything other than people.

(Thanks to Ewald Schnug and Silvia Haneklaus for bringing this to my attention.)

· Marc Abrahams is editor of the bimonthly Annals of Improbable Research and organiser of the Ig Nobel prize